1. Field of the Invention
The present invention relates to a robot controller controlling robots used combined with machine tools.
2. Description of the Related Art
The work of supplying a workpiece material to a machine tool and the work of taking out a finished workpiece machined by the machine tool from the machine tool are together called “loading and unloading work”. A machine tool is expensive, so operating it for a full 24 hours is preferable, but to accomplish that, the workers performing the loading and unloading work have to be made to work for long hours.
However, workplaces for processing workpiece materials by machine tools are hostile environments with cutting oil and dust from deburring in the air. Further, when the weight of the workpiece is comparatively heavy, there are times when the worker is physically at risk. Therefore, it is difficult for workers to perform loading and unloading work for long periods of time. Thus, loading and unloading work by robots instead of workers is desirable (see Japanese Unexamined Patent Publication (A) No. 7-114402).
When robots are used in place of workers, for using the machine tool and robot in combination, various start-up work is necessary when installing the machine tool and robot.
For example, various interlock signals have to be sent and received through a signal cable between the machine tool and robot. For such signal transmission, a signal cable has to be suitably laid between the machine tool and robot, and the machine tool and robot set so as to be able to accurately send and receive signals. Note that, as a signal cable, an analog signal cable or a network handling digital signals is used.
Interlock signals sent and received between the robot and machine tool differ depending on the work content of the robot in the production system, so the logical meaning of each signal also differs for each production system. The work for setting which signal of the robot to connect with which signal of the machine tool and what logical meaning each signal has is called “signal assignment work”.
Such signal assignment work is carried out manually and thus takes an extremely long time when the number of signals is high. Further, the signal assignment work must be carried out on both the robot and machine tool. Further, when accurate assignment work is not carried out on both the robot and machine tool, the signal output from either the robot or machine tool will end up being input for a signal with a different meaning at the other of the robot or machine tool causing a problem of the interlock not properly working.
Further, it is necessary to set a coordinate system common to the robot and machine tool in both the robot and machine tool matching the relative positional relationship of the robot and machine tool and define the loading and unloading operations of the robot based on this common coordinate system. For example, the standby position until the automatic door of the machine tool opens, the entry path into the machine tool, the position of holding the workpiece, the exit path to outside of the machine tool, and the like are set using this common coordinate system in the robot.
Similarly, in the machine tool also, the finished workpiece must be moved to the holding position of the robot using the common coordinate system. The common coordinate system is thereby crucial for the operations of both the robot and machine tool. When the coordinate system of the robot and the coordinate system of the machine tool differ, loading and unloading work of a workpiece cannot be carried out accurately.
Further, the relative correspondence of the machining program run at the machine tool and the loading and unloading work program run at the robot must be set in both the machine tool and robot. When machining different types of workpieces with a machine tool, machining programs differing for each type of workpiece are run at the machine tool. Similarly, when loading and unloading different types of workpieces with a robot, the position and posture for holding each workpiece differ, so a loading and unloading work program must be prepared for each type of workpiece.
It is necessary to prepare a part number for each type of workpiece, set the machining program to be run for the part number at the machine tool, and set the work program to be run for the part number at the robot. Preferably, the robot is informed of the part number of the workpiece by the machine tool with an interlock signal, and the loading and unloading work program corresponding to the part number is automatically run by the robot. However, if a conflict is generated in the relative correspondence of the machining program of the machine tool and the work program of the robot, the workpiece cannot be accurately loaded and unloaded.
In cases when a robot is used for loading and unloading work of a workpiece to and from a machine tool, when installing and starting up the machine tool, it is necessary to carry out, in addition to the machine tool startup work, startup work for each setting with respect to the robot as well. Further, the contents of the machine tool startup work and the robot startup work differ, so both an operator well versed in machine tools and an operator well versed in robots are necessary. In this way, to start up one production system, there must be two operators, so training costs and training periods to train such operators are necessary.
Further, not only do the man-hours for robot startup work increase, but also steps for connecting to the robot, which had been conventionally unnecessary in the past, are needed in machine tool startup. Therefore, such additional steps will increase the startup costs. The increase in startup costs is a problem when using a robot for loading and unloading work of a workpiece at a machine tool.
Further, even when the cost problems could be solved, since the machine tool startup operator and the robot startup operator were different, there had been cases of inconsistencies between the contents of the settings of the machine tool and the contents of the settings of the robot. In particular, when there were different types of machine tools and/or different types of robots, the contents of startup work also differed according to the types of machine tools and robots, so a high level of skill was necessary. Therefore, a purchaser of the machine tools and robots had to study the startup work for both or else employ startup workers or could not use the machine tools and robots.
The present invention was created in light of this situation and has as its object to provide a robot controller able to simply and easily perform machine tool and robot startup work without requiring skill or increasing startup man-hours.